1. Technical Field
The present invention relates to inspection on an ejection state of a liquid ejection apparatus.
2. Related Art
An ink jet type printer (hereinafter, referred to as an “ink jet printer”) performs printing by ejecting an ink in a cavity. The ink is thickened when dried. When the ink in the cavity is thickened, this might cause ejection failure. In addition, when bubbles are included in the ink in the cavity or paper dust is adhered to a nozzle which ejects the ink, this might cause ejection failure as well. Accordingly, it is preferable that the ejection state of the ink be inspected.
JP-A-2004-299341 (FIG. 26) discloses a method of vibrating an ink in the cavity using a piezoelectric element and determining the ejection state by sensing behavior of the ink with respect to the residual vibration.
However, in the ink used for the liquid ejection apparatus, an ink of a pigment component contained in the ink with a high sedimentation velocity is present in terms of a color matter or a solvent. In the present specification, the term “sedimentation” means that components (for example, a pigment component) contained in a liquid (for example, an ink) are settled and the components contained in the liquid are accumulated on a lower layer of the liquid in a case where the liquid is left alone for a certain period of time. As sedimentation components of the white ink, a white pigment can be exemplified and a component linked thereto or adsorbed by the white pigment is contained.
Particularly, in the white ink, sedimentation of the pigment component tends to occur in terms of the composition thereof. In a case where such an ink is ejected, unevenness in the component occurs due to the sedimentation and an image is unstably formed during the time between the ink is filled in the cavity and then ejected therefrom.
However, in the technology in the related art, it is possible to determine whether the ink is thickened but not possible to determine whether the pigment component of the ink is sedimented.